Best exhaust sealant. How to choose it

What is exhaust sealant good for?

The exhaust sealant allows you to repair the exhaust pipes for your car, in case of damage, without removing it. Because its elements work in very rough conditions, such as constant temperature changes, moisture, dirt, and exposure to harmful substances directly in the exhaust gases, at one point they will wear out and will rust.

Condensation is accumulated there, especially in the muffler that will cause the rust to appear.

Why do exhaust elements wear out?

Damage to the exhaust system are cause by the above factors together with impurities or dirt that enters the exhaust system will cause its material to wear out.

  • Frequent temperature changes at which the exhaust is operating, especially if you drive short distances in the cold season.
  • Low-quality material of the exhaust pipes or other parts of it
  • Burnout of pipes, muffler, or other parts;
  • Mechanical damage to the exhaust elements. For example, driving on a bad road.

Repairing the exhaust system elements

There are two ways to repair damaged exhaust pipes, either by welding, and for this method you will need to remove the exhaust elements, or by using a special sealant that does the same thing without removing the exhaust elements from the car.

The symptoms for their damage is easy to notice since the sound emitted is often associated with a sound similar to a the race car.

When to use the exhaust system sealant

Sealants are from heat-resistant ceramic or elastic material that ensures the tightness of the system. When choosing a proper sealant for repairing, you need to pay attention to its maximum operating temperature, performance characteristics, ease of use, durability, warranty period, etc.

The sealant for the exhaust system is used, most cases on

  • To cover cracks on the exhaust elements
  • When repairing a muffler to cover cracks, or when, if a metal patch is used to repair the muffler, then in addition to the fasteners, it must also be mounted with a sealant.
  • Elements of the new exhaust system.

How to choose the best exhaust system sealant

Because a lot of sealants are available on the store today, you should carefully read its description and consider the following aspects:

Sealant type

Exhaust sealants are mostly based on silicon and ceramic. The main difference between silicone sealants and ceramic sealant is that silicone sealant, after hardening, it will remain slightly mobile and does not lose its properties with vibration or small shifts of the processed parts. These are used on gaskets when connecting elements of the exhaust system.

Ceramic sealants, after hardening, will become completely immobile, used mainly to fill larger cracks or holes caused by rust. You can find them in stores in the form of paste or cement. However, their disadvantage is that they may crack at vibrations.

Thus, cement is used for more serious repairs, and you should opt for a silicon based sealant otherwise.

Sealant types all come with their different forms, characteristics and performances

  • Cement. Used for difficult repairs, this type can be used to repair only fixed parts, muffler housings, resonator, as well as for processing joints. As a disadvantage, it dries very quickly when exposed to high temperatures.
  • Adhesive for repairing exhaust elements. Being made on the basis of fiberglass and extra additives, these products are intended for sealing small holes and/or cracks in the exhaust pipe and other parts. As for advantages, it solidifies in about 10 minutes and is resistant to thermal changes, but under mechanical stress, it can crack.
  • Muffler sealant. Used both as a prophylactic and repair agent, it is based on silicon with other additives. Silicone sealant can be used directly in muffler, pipes, resonator, exhaust manifold
  • Mounting paste. It is usually used when installing new parts or when repairing and installing used ones. Influenced by high temperatures, the paste quickly hardens and keeps its good properties for a long time.

Alternatives to sealants

Heated wraps. A good alternative to regular types of sealants, it can be a solution to tears and cracks and works very well in repairing those types of damage.

Temperature working range

The temperature is a very important indicator, the higher it is, the better. Logically, this will mean that the sealant will maintain its working properties at high temperatures, but this is not entirely true. Manufacturers mislead consumers by specifying the maximum temperature that the sealant can handle for only a short time. Naturally, this value will be higher. 

Thus, you will need to look not only at the maximum allowable temperature value, but also at the time that the sealant is designed to resist at this temperature.

Tips for repairing the exhaust with sealant

Firstly, you should use sealant as a temporary measure or to repair minor damage to the exhaust system. In case of significant damage, like larger rotten holes, you need to change the element.

  • Before using the sealant, you should clean the area on the exhaust of debris, rust, moisture, and dirt. Ideally, you should also degrease the area, since not all sealants are resistant to oil.
  • The sealant should be applied evenly. The paste for the exhaust system squeezed out from under the adjoining surfaces must be carefully removed.
  • The sealant usually hardens for at least one to three hours at a normal temperature. The exact information is written in the instructions.
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